The 23-time Grand Slam singles champion Serena Williams has been forced to withdraw from the Rothesay International at Eastbourne due to an injury to her doubles partner Ons Jabeur.
A right knee injury to Jabeur, led to them withdrawing from the grass-court event in Eastbourne, the WTA said on Thursday.
There was no immediate news about the seriousness of Jabeur's injury.
Playing in her first event on tour since suffering an injury at last year's Wimbledon, the 40-year-old Serena has found a winning combination by pairing with singles World No.3 Jabeur for the first time.
They were scheduled to play Magda Linette and Aleksandra Krunic in the semifinals after winning two matches so far in the event.
The American and Tunisian partner made it through to the semifinals with a narrow win over Maria Bouzkova and Sara Sorribes Tormo, before a more convincing quarterfinal victory in straight sets against Shuko Aoyama and Chan Hao-ching.
Serena will now focus on Wimbledon where she has accepted a wild card into the women's singles in a bid to win a record-equalling 24th Grand Slam title.